2021 Subaru Ascent BaseFACTORY OEM SERVICE PROCEDURE

Basic Diagnostic Procedure: Procedure

  1. CHECK PRE-INSPECTION  .
    1. Ask the customer when and how the trouble occurred using the interview check list. Ref. to TRANSMISSION (DIAGNOSTICS)>CHECK LIST FOR INTERVIEW .
    2. Before performing diagnostics, check the following items which might affect CVT problems.
      • General inspection. Ref. to TRANSMISSION (DIAGNOSTICS)>General Description>INSPECTION .
      • Disconnection of harness connector
      • Visual check for harness damage
      • Oil leakage
      • Stall speed test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>STALL TEST .
      • Secondary pressure test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>SECONDARY PRESSURE TEST .
      • Line pressure test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>LINE PRESSURE TEST .
      • Transfer clutch pressure test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSFER CLUTCH PRESSURE TEST .
      • Time lag test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TIME LAG TEST .
      • ROAD TEST. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>ROAD TEST .
      • Inhibitor switch. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>INHIBITOR SWITCH .

      Is the check result OK?

      Yes  : Go to  2.

      No  : Repair the items which may be affecting the CVT trouble.

  2. CHECK AT OIL TEMP LIGHT  .

    Turn the ignition switch to ON and wait for at least 2 seconds.

    Does the AT OIL TEMP light illuminate?

    Yes  : Go to  3.

    No  : Check the AT OIL TEMP light.

  3. CHECK AT OIL TEMP LIGHT  .

    Start the engine and wait for 2 seconds or more.

    Does the AT OIL TEMP light blink?

    Yes  : Go to  4.

    No  : Go to  5.

  4. CHECK DTC  .

    Read the DTC using Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

    NOTE: If the communication function of Subaru Select Monitor cannot be executed normally, check the communication circuit. Ref. to TRANSMISSION (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE FOR SUBARU SELECT MONITOR COMMUNICATION .

    Are any DTCs displayed?

    Yes  : Record the DTC, time stamp and freeze frame data. Turn the ignition switch to OFF and wait for 30 seconds. Go to  6.

    No  : Go to  5.

  5. PERFORM GENERAL DIAGNOSTICS  .
    1. Inspect using "Diagnostic Procedure without Diagnostic Trouble Code (DTC)". Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Procedure without Diagnostic Trouble Code (DTC) .
    2. Inspect using "Diagnostics with Phenomenon". Ref. to TRANSMISSION (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON .
    3. Perform the road test. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>ROAD TEST .
    4. Read the DTC using Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

      Are any DTCs displayed?

      Yes  : Go to  6.

      No  : Finish the diagnosis.

  6. PERFORM DIAGNOSIS  .
    1. Inspect by referring to "Diagnostic Procedure with Diagnostic Trouble Code (DTC)". Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC) .
      NOTE: For the DTC table, refer to "Diagnostic Trouble Code (DTC)". Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)>LIST .
    2. Repair the trouble cause.
    3. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (diag)>CLEAR MEMORY .
    4. Execute the inspection mode. Ref. to TRANSMISSION (DIAGNOSTICS)>INSPECTION MODE .
    5. Check the readiness code using Subaru Select Monitor and confirm that the diagnosis is completed. Ref. to TRANSMISSION (DIAGNOSTICS)>All Readiness Diagnostic Code(s) .
    6. Read the DTC using Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

      Are any DTCs displayed?

      Yes  : Inspect by referring to "Diagnostic Procedure with Diagnostic Trouble Code (DTC)". Ref. to TRANSMISSION (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC) .

      No  : Finish the diagnosis.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.